2014 Volume 9 Issue 3 Pages 309-322
On the 19th January in 2011, a phreatomagmatic eruption occurred at Mt. Shinmoedake in the Kirishima volcanoes group of Kyushu Island. Large amount of volcanic ashes were falling in the surrounding areas. It was reported that over 40 million tons volcanic ashes were deposited on the surrounding city. In this paper, a series of soil tests are carried out a volcanic ash deposit originating from Mt. Shinmoedake. The approach employed in these soil tests was as follows: 1) physical properties tests, 2) compaction test, 3) undrained cyclic shear test and 4) slaking test. In addition, this paper compares the geotechnical properties of volcanic ash deposits originating from Mt. Shinmoedake with those of other volcanic ash deposits and typical silica sand. As a result, geotechnical characteristics of volcanic ash deposits originating from Mt. Shinmoedake were similar to those of sandy soil in practice. However, it is predicted that geotechnical characteristics of this volcanic ash deposits will change due to the influence of physical weathering.
